I deleted a user, but they are still able to add receipts using their app. How can I permantly delete this user so they have no access?

Great having you join us here in the Community, @suzan-saturno. I'm happy to address your concern about deleting a user in QuickBooks Online.

I can see you have posted the same concern twice in the QBO Community. My colleague already shared their response on the other thread. You may refer to this link to review the solution to your concern.

In addition, I've got this helpful resource you can use as a guide if you encounter a problem inviting users into QuickBooks Online.

I'll be around if you need further assistance about managing your users in QBO. I'm very eager to help. Take care!